Commit 68ea60a7 authored by Li Zhijian's avatar Li Zhijian Committed by Julia Lawall
Browse files

coccinelle: device_attr_show: Adapt to the latest Documentation/filesystems/sysfs.rst 



Adapt description, warning message and MODE=patch according to the latest
Documentation/filesystems/sysfs.rst:
> show() should only use sysfs_emit() or sysfs_emit_at() when formatting
> the value to be returned to user space.

After this patch:
When MODE=report,
 $ make coccicheck COCCI=scripts/coccinelle/api/device_attr_show.cocci M=drivers/hid/hid-picolcd_core.c MODE=report
 <...snip...>
 drivers/hid/hid-picolcd_core.c:304:8-16: WARNING: please use sysfs_emit or sysfs_emit_at
 drivers/hid/hid-picolcd_core.c:259:9-17: WARNING: please use sysfs_emit or sysfs_emit_at

When MODE=patch,
 $ make coccicheck COCCI=scripts/coccinelle/api/device_attr_show.cocci M=drivers/hid/hid-picolcd_core.c MODE=patch
 <...snip...>
 diff -u -p a/drivers/hid/hid-picolcd_core.c b/drivers/hid/hid-picolcd_core.c
 --- a/drivers/hid/hid-picolcd_core.c
 +++ b/drivers/hid/hid-picolcd_core.c
 @@ -255,10 +255,12 @@ static ssize_t picolcd_operation_mode_sh
  {
         struct picolcd_data *data = dev_get_drvdata(dev);

 -       if (data->status & PICOLCD_BOOTLOADER)
 -               return snprintf(buf, PAGE_SIZE, "[bootloader] lcd\n");
 -       else
 -               return snprintf(buf, PAGE_SIZE, "bootloader [lcd]\n");
 +       if (data->status & PICOLCD_BOOTLOADER) {
 +               return sysfs_emit(buf, "[bootloader] lcd\n");
 +       }
 +       else {
 +               return sysfs_emit(buf, "bootloader [lcd]\n");
 +       }
  }

  static ssize_t picolcd_operation_mode_store(struct device *dev,
 @@ -301,7 +303,7 @@ static ssize_t picolcd_operation_mode_de
  {
         struct picolcd_data *data = dev_get_drvdata(dev);

 -       return snprintf(buf, PAGE_SIZE, "hello world\n");
 +       return sysfs_emit(buf, "hello world\n");
  }

  static ssize_t picolcd_operation_mode_delay_store(struct device *dev,

CC: Julia Lawall <Julia.Lawall@inria.fr>
CC: Nicolas Palix <nicolas.palix@imag.fr>
CC: cocci@inria.fr
Signed-off-by: default avatarLi Zhijian <lizhijian@fujitsu.com>
parent 556e2d17

scripts/coccinelle/api/device_attr_show.cocci

+13 −9
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

///

/// From Documentation/filesystems/sysfs.rst:

///  show() must not use snprintf() when formatting the value to be

///  returned to user space. If you can guarantee that an overflow

///  will never happen you can use sprintf() otherwise you must use

///  scnprintf().

///  show() should only use sysfs_emit() or sysfs_emit_at() when formatting

///  the value to be returned to user space.

///

// Confidence: High

// Copyright: (C) 2020 Denis Efremov ISPRAS
@@ -30,15 +28,21 @@ ssize_t show(struct device *dev, struct device_attribute *attr, char *buf) 


@rp depends on patch@

identifier show, dev, attr, buf;

expression BUF, SZ, FORMAT, STR;

@@



ssize_t show(struct device *dev, struct device_attribute *attr, char *buf)

{

	<...

(

	return

-		snprintf

+		scnprintf

			(...);

-		snprintf(BUF, SZ, FORMAT, STR);

+		sysfs_emit(BUF, FORMAT, STR);

|

	return

-		snprintf(BUF, SZ, STR);

+		sysfs_emit(BUF, STR);

)

	...>

}
@@ -46,10 +50,10 @@ ssize_t show(struct device *dev, struct device_attribute *attr, char *buf) 
p << r.p;

@@



coccilib.report.print_report(p[0], "WARNING: use scnprintf or sprintf")

coccilib.report.print_report(p[0], "WARNING: please use sysfs_emit or sysfs_emit_at")



@script: python depends on org@

p << r.p;

@@



coccilib.org.print_todo(p[0], "WARNING: use scnprintf or sprintf")
 
coccilib.org.print_todo(p[0], "WARNING: please use sysfs_emit or sysfs_emit_at")